[deliverable/linux.git] / sound / core / oss / mulaw.c

/*
 *  Mu-Law conversion Plug-In Interface
 *  Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>
 *                        Uros Bizjak <uros@kss-loka.si>
 *
 *  Based on reference implementation by Sun Microsystems, Inc.
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as
 *   published by the Free Software Foundation; either version 2 of
 *   the License, or (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */
  
#include <sound/driver.h>

#ifdef CONFIG_SND_PCM_OSS_PLUGINS

#include <linux/time.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include "pcm_plugin.h"

#define	SIGN_BIT	(0x80)		/* Sign bit for a u-law byte. */
#define	QUANT_MASK	(0xf)		/* Quantization field mask. */
#define	NSEGS		(8)		/* Number of u-law segments. */
#define	SEG_SHIFT	(4)		/* Left shift for segment number. */
#define	SEG_MASK	(0x70)		/* Segment field mask. */

static inline int val_seg(int val)
{
	int r = 0;
	val >>= 7;
	if (val & 0xf0) {
		val >>= 4;
		r += 4;
	}
	if (val & 0x0c) {
		val >>= 2;
		r += 2;
	}
	if (val & 0x02)
		r += 1;
	return r;
}

#define	BIAS		(0x84)		/* Bias for linear code. */

/*
 * linear2ulaw() - Convert a linear PCM value to u-law
 *
 * In order to simplify the encoding process, the original linear magnitude
 * is biased by adding 33 which shifts the encoding range from (0 - 8158) to
 * (33 - 8191). The result can be seen in the following encoding table:
 *
 *	Biased Linear Input Code	Compressed Code
 *	------------------------	---------------
 *	00000001wxyza			000wxyz
 *	0000001wxyzab			001wxyz
 *	000001wxyzabc			010wxyz
 *	00001wxyzabcd			011wxyz
 *	0001wxyzabcde			100wxyz
 *	001wxyzabcdef			101wxyz
 *	01wxyzabcdefg			110wxyz
 *	1wxyzabcdefgh			111wxyz
 *
 * Each biased linear code has a leading 1 which identifies the segment
 * number. The value of the segment number is equal to 7 minus the number
 * of leading 0's. The quantization interval is directly available as the
 * four bits wxyz.  * The trailing bits (a - h) are ignored.
 *
 * Ordinarily the complement of the resulting code word is used for
 * transmission, and so the code word is complemented before it is returned.
 *
 * For further information see John C. Bellamy's Digital Telephony, 1982,
 * John Wiley & Sons, pps 98-111 and 472-476.
 */
static unsigned char linear2ulaw(int pcm_val)	/* 2's complement (16-bit range) */
{
	int mask;
	int seg;
	unsigned char uval;

	/* Get the sign and the magnitude of the value. */
	if (pcm_val < 0) {
		pcm_val = BIAS - pcm_val;
		mask = 0x7F;
	} else {
		pcm_val += BIAS;
		mask = 0xFF;
	}
	if (pcm_val > 0x7FFF)
		pcm_val = 0x7FFF;

	/* Convert the scaled magnitude to segment number. */
	seg = val_seg(pcm_val);

	/*
	 * Combine the sign, segment, quantization bits;
	 * and complement the code word.
	 */
	uval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0xF);
	return uval ^ mask;
}

/*
 * ulaw2linear() - Convert a u-law value to 16-bit linear PCM
 *
 * First, a biased linear code is derived from the code word. An unbiased
 * output can then be obtained by subtracting 33 from the biased code.
 *
 * Note that this function expects to be passed the complement of the
 * original code word. This is in keeping with ISDN conventions.
 */
static int ulaw2linear(unsigned char u_val)
{
	int t;

	/* Complement to obtain normal u-law value. */
	u_val = ~u_val;

	/*
	 * Extract and bias the quantization bits. Then
	 * shift up by the segment number and subtract out the bias.
	 */
	t = ((u_val & QUANT_MASK) << 3) + BIAS;
	t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;

	return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
}

/*
 *  Basic Mu-Law plugin
 */

typedef void (*mulaw_f)(struct snd_pcm_plugin *plugin,
			const struct snd_pcm_plugin_channel *src_channels,
			struct snd_pcm_plugin_channel *dst_channels,
			snd_pcm_uframes_t frames);

struct mulaw_priv {
	mulaw_f func;
	int conv;
};

static void mulaw_decode(struct snd_pcm_plugin *plugin,
			const struct snd_pcm_plugin_channel *src_channels,
			struct snd_pcm_plugin_channel *dst_channels,
			snd_pcm_uframes_t frames)
{
#define PUT_S16_LABELS
#include "plugin_ops.h"
#undef PUT_S16_LABELS
	struct mulaw_priv *data = (struct mulaw_priv *)plugin->extra_data;
	void *put = put_s16_labels[data->conv];
	int channel;
	int nchannels = plugin->src_format.channels;
	for (channel = 0; channel < nchannels; ++channel) {
		char *src;
		char *dst;
		int src_step, dst_step;
		snd_pcm_uframes_t frames1;
		if (!src_channels[channel].enabled) {
			if (dst_channels[channel].wanted)
				snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
			dst_channels[channel].enabled = 0;
			continue;
		}
		dst_channels[channel].enabled = 1;
		src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
		dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
		src_step = src_channels[channel].area.step / 8;
		dst_step = dst_channels[channel].area.step / 8;
		frames1 = frames;
		while (frames1-- > 0) {
			signed short sample = ulaw2linear(*src);
			goto *put;
#define PUT_S16_END after
#include "plugin_ops.h"
#undef PUT_S16_END
		after:
			src += src_step;
			dst += dst_step;
		}
	}
}

static void mulaw_encode(struct snd_pcm_plugin *plugin,
			const struct snd_pcm_plugin_channel *src_channels,
			struct snd_pcm_plugin_channel *dst_channels,
			snd_pcm_uframes_t frames)
{
#define GET_S16_LABELS
#include "plugin_ops.h"
#undef GET_S16_LABELS
	struct mulaw_priv *data = (struct mulaw_priv *)plugin->extra_data;
	void *get = get_s16_labels[data->conv];
	int channel;
	int nchannels = plugin->src_format.channels;
	signed short sample = 0;
	for (channel = 0; channel < nchannels; ++channel) {
		char *src;
		char *dst;
		int src_step, dst_step;
		snd_pcm_uframes_t frames1;
		if (!src_channels[channel].enabled) {
			if (dst_channels[channel].wanted)
				snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
			dst_channels[channel].enabled = 0;
			continue;
		}
		dst_channels[channel].enabled = 1;
		src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
		dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
		src_step = src_channels[channel].area.step / 8;
		dst_step = dst_channels[channel].area.step / 8;
		frames1 = frames;
		while (frames1-- > 0) {
			goto *get;
#define GET_S16_END after
#include "plugin_ops.h"
#undef GET_S16_END
		after:
			*dst = linear2ulaw(sample);
			src += src_step;
			dst += dst_step;
		}
	}
}

static snd_pcm_sframes_t mulaw_transfer(struct snd_pcm_plugin *plugin,
			      const struct snd_pcm_plugin_channel *src_channels,
			      struct snd_pcm_plugin_channel *dst_channels,
			      snd_pcm_uframes_t frames)
{
	struct mulaw_priv *data;

	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
	if (frames == 0)
		return 0;
#ifdef CONFIG_SND_DEBUG
	{
		unsigned int channel;
		for (channel = 0; channel < plugin->src_format.channels; channel++) {
			snd_assert(src_channels[channel].area.first % 8 == 0 &&
				   src_channels[channel].area.step % 8 == 0,
				   return -ENXIO);
			snd_assert(dst_channels[channel].area.first % 8 == 0 &&
				   dst_channels[channel].area.step % 8 == 0,
				   return -ENXIO);
		}
	}
#endif
	data = (struct mulaw_priv *)plugin->extra_data;
	data->func(plugin, src_channels, dst_channels, frames);
	return frames;
}

int snd_pcm_plugin_build_mulaw(struct snd_pcm_substream *plug,
			       struct snd_pcm_plugin_format *src_format,
			       struct snd_pcm_plugin_format *dst_format,
			       struct snd_pcm_plugin **r_plugin)
{
	int err;
	struct mulaw_priv *data;
	struct snd_pcm_plugin *plugin;
	struct snd_pcm_plugin_format *format;
	mulaw_f func;

	snd_assert(r_plugin != NULL, return -ENXIO);
	*r_plugin = NULL;

	snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);

	if (dst_format->format == SNDRV_PCM_FORMAT_MU_LAW) {
		format = src_format;
		func = mulaw_encode;
	}
	else if (src_format->format == SNDRV_PCM_FORMAT_MU_LAW) {
		format = dst_format;
		func = mulaw_decode;
	}
	else {
		snd_BUG();
		return -EINVAL;
	}
	snd_assert(snd_pcm_format_linear(format->format) != 0, return -ENXIO);

	err = snd_pcm_plugin_build(plug, "Mu-Law<->linear conversion",
				   src_format, dst_format,
				   sizeof(struct mulaw_priv), &plugin);
	if (err < 0)
		return err;
	data = (struct mulaw_priv *)plugin->extra_data;
	data->func = func;
	data->conv = getput_index(format->format);
	snd_assert(data->conv >= 0 && data->conv < 4*2*2, return -EINVAL);
	plugin->transfer = mulaw_transfer;
	*r_plugin = plugin;
	return 0;
}

#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Mu-Law conversion Plug-In Interface
	3	* Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>
	4	* Uros Bizjak <uros@kss-loka.si>
	5	*
	6	* Based on reference implementation by Sun Microsystems, Inc.
	7	*
	8	* This library is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU Library General Public License as
	10	* published by the Free Software Foundation; either version 2 of
	11	* the License, or (at your option) any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU Library General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Library General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	21	*
	22	*/
	23
	24	#include <sound/driver.h>
21a3479a JK	25
	26	#ifdef CONFIG_SND_PCM_OSS_PLUGINS
	27
1da177e4 LT	28	#include <linux/time.h>
	29	#include <sound/core.h>
	30	#include <sound/pcm.h>
	31	#include "pcm_plugin.h"
	32
	33	#define SIGN_BIT (0x80) /* Sign bit for a u-law byte. */
	34	#define QUANT_MASK (0xf) /* Quantization field mask. */
	35	#define NSEGS (8) /* Number of u-law segments. */
	36	#define SEG_SHIFT (4) /* Left shift for segment number. */
	37	#define SEG_MASK (0x70) /* Segment field mask. */
	38
	39	static inline int val_seg(int val)
	40	{
	41	int r = 0;
	42	val >>= 7;
	43	if (val & 0xf0) {
	44	val >>= 4;
	45	r += 4;
	46	}
	47	if (val & 0x0c) {
	48	val >>= 2;
	49	r += 2;
	50	}
	51	if (val & 0x02)
	52	r += 1;
	53	return r;
	54	}
	55
	56	#define BIAS (0x84) /* Bias for linear code. */
	57
	58	/*
	59	* linear2ulaw() - Convert a linear PCM value to u-law
	60	*
	61	* In order to simplify the encoding process, the original linear magnitude
	62	* is biased by adding 33 which shifts the encoding range from (0 - 8158) to
	63	* (33 - 8191). The result can be seen in the following encoding table:
	64	*
	65	* Biased Linear Input Code Compressed Code
	66	* ------------------------ ---------------
	67	* 00000001wxyza 000wxyz
	68	* 0000001wxyzab 001wxyz
	69	* 000001wxyzabc 010wxyz
	70	* 00001wxyzabcd 011wxyz
	71	* 0001wxyzabcde 100wxyz
	72	* 001wxyzabcdef 101wxyz
	73	* 01wxyzabcdefg 110wxyz
	74	* 1wxyzabcdefgh 111wxyz
	75	*
	76	* Each biased linear code has a leading 1 which identifies the segment
	77	* number. The value of the segment number is equal to 7 minus the number
	78	* of leading 0's. The quantization interval is directly available as the
	79	* four bits wxyz. * The trailing bits (a - h) are ignored.
	80	*
	81	* Ordinarily the complement of the resulting code word is used for
	82	* transmission, and so the code word is complemented before it is returned.
	83	*
	84	* For further information see John C. Bellamy's Digital Telephony, 1982,
	85	* John Wiley & Sons, pps 98-111 and 472-476.
	86	*/
	87	static unsigned char linear2ulaw(int pcm_val) /* 2's complement (16-bit range) */
	88	{
	89	int mask;
	90	int seg;
	91	unsigned char uval;
92
93	/* Get the sign and the magnitude of the value. */
94	if (pcm_val < 0) {
95	pcm_val = BIAS - pcm_val;
96	mask = 0x7F;
97	} else {
98	pcm_val += BIAS;
99	mask = 0xFF;
100	}
101	if (pcm_val > 0x7FFF)
102	pcm_val = 0x7FFF;
103
104	/* Convert the scaled magnitude to segment number. */
105	seg = val_seg(pcm_val);
106
107	/*
108	* Combine the sign, segment, quantization bits;
109	* and complement the code word.
110	*/
111	uval = (seg << 4) \| ((pcm_val >> (seg + 3)) & 0xF);
112	return uval ^ mask;
113	}
114
115	/*
116	* ulaw2linear() - Convert a u-law value to 16-bit linear PCM
117	*
118	* First, a biased linear code is derived from the code word. An unbiased
119	* output can then be obtained by subtracting 33 from the biased code.
120	*
121	* Note that this function expects to be passed the complement of the
122	* original code word. This is in keeping with ISDN conventions.
123	*/
124	static int ulaw2linear(unsigned char u_val)
125	{
126	int t;
127
128	/* Complement to obtain normal u-law value. */
129	u_val = ~u_val;
130
131	/*
132	* Extract and bias the quantization bits. Then
133	* shift up by the segment number and subtract out the bias.
134	*/
135	t = ((u_val & QUANT_MASK) << 3) + BIAS;
136	t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
137
138	return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
139	}
140
141	/*
142	* Basic Mu-Law plugin
143	*/
144
6ac77bc1 TI	145	typedef void (mulaw_f)(struct snd_pcm_plugin plugin,
	146	const struct snd_pcm_plugin_channel *src_channels,
	147	struct snd_pcm_plugin_channel *dst_channels,
1da177e4 LT	148	snd_pcm_uframes_t frames);
1da177e4 LT	149
6ac77bc1	150	struct mulaw_priv {
1da177e4 LT	151	mulaw_f func;
1da177e4 LT	152	int conv;
6ac77bc1	153	};
1da177e4	154
6ac77bc1 TI	155	static void mulaw_decode(struct snd_pcm_plugin *plugin,
	156	const struct snd_pcm_plugin_channel *src_channels,
	157	struct snd_pcm_plugin_channel *dst_channels,
1da177e4 LT	158	snd_pcm_uframes_t frames)
	159	{
	160	#define PUT_S16_LABELS
	161	#include "plugin_ops.h"
	162	#undef PUT_S16_LABELS
6ac77bc1	163	struct mulaw_priv data = (struct mulaw_priv )plugin->extra_data;
1da177e4 LT	164	void *put = put_s16_labels[data->conv];
	165	int channel;
	166	int nchannels = plugin->src_format.channels;
	167	for (channel = 0; channel < nchannels; ++channel) {
	168	char *src;
	169	char *dst;
	170	int src_step, dst_step;
	171	snd_pcm_uframes_t frames1;
	172	if (!src_channels[channel].enabled) {
	173	if (dst_channels[channel].wanted)
	174	snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
	175	dst_channels[channel].enabled = 0;
	176	continue;
	177	}
	178	dst_channels[channel].enabled = 1;
	179	src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
	180	dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
	181	src_step = src_channels[channel].area.step / 8;
	182	dst_step = dst_channels[channel].area.step / 8;
	183	frames1 = frames;
	184	while (frames1-- > 0) {
	185	signed short sample = ulaw2linear(*src);
	186	goto *put;
	187	#define PUT_S16_END after
	188	#include "plugin_ops.h"
	189	#undef PUT_S16_END
	190	after:
	191	src += src_step;
	192	dst += dst_step;
	193	}
	194	}
	195	}
	196
6ac77bc1 TI	197	static void mulaw_encode(struct snd_pcm_plugin *plugin,
	198	const struct snd_pcm_plugin_channel *src_channels,
	199	struct snd_pcm_plugin_channel *dst_channels,
1da177e4 LT	200	snd_pcm_uframes_t frames)
	201	{
	202	#define GET_S16_LABELS
	203	#include "plugin_ops.h"
	204	#undef GET_S16_LABELS
6ac77bc1	205	struct mulaw_priv data = (struct mulaw_priv )plugin->extra_data;
1da177e4 LT	206	void *get = get_s16_labels[data->conv];
	207	int channel;
	208	int nchannels = plugin->src_format.channels;
	209	signed short sample = 0;
	210	for (channel = 0; channel < nchannels; ++channel) {
	211	char *src;
	212	char *dst;
	213	int src_step, dst_step;
	214	snd_pcm_uframes_t frames1;
	215	if (!src_channels[channel].enabled) {
	216	if (dst_channels[channel].wanted)
	217	snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
	218	dst_channels[channel].enabled = 0;
	219	continue;
	220	}
	221	dst_channels[channel].enabled = 1;
	222	src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
	223	dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
	224	src_step = src_channels[channel].area.step / 8;
	225	dst_step = dst_channels[channel].area.step / 8;
	226	frames1 = frames;
	227	while (frames1-- > 0) {
	228	goto *get;
	229	#define GET_S16_END after
	230	#include "plugin_ops.h"
	231	#undef GET_S16_END
	232	after:
	233	*dst = linear2ulaw(sample);
	234	src += src_step;
	235	dst += dst_step;
	236	}
	237	}
	238	}
	239
6ac77bc1 TI	240	static snd_pcm_sframes_t mulaw_transfer(struct snd_pcm_plugin *plugin,
	241	const struct snd_pcm_plugin_channel *src_channels,
	242	struct snd_pcm_plugin_channel *dst_channels,
1da177e4 LT	243	snd_pcm_uframes_t frames)
1da177e4 LT	244	{
6ac77bc1	245	struct mulaw_priv *data;
1da177e4 LT	246
	247	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
	248	if (frames == 0)
	249	return 0;
	250	#ifdef CONFIG_SND_DEBUG
	251	{
	252	unsigned int channel;
	253	for (channel = 0; channel < plugin->src_format.channels; channel++) {
	254	snd_assert(src_channels[channel].area.first % 8 == 0 &&
	255	src_channels[channel].area.step % 8 == 0,
	256	return -ENXIO);
	257	snd_assert(dst_channels[channel].area.first % 8 == 0 &&
	258	dst_channels[channel].area.step % 8 == 0,
	259	return -ENXIO);
	260	}
	261	}
	262	#endif
6ac77bc1	263	data = (struct mulaw_priv *)plugin->extra_data;
1da177e4 LT	264	data->func(plugin, src_channels, dst_channels, frames);
	265	return frames;
	266	}
	267
6ac77bc1 TI	268	int snd_pcm_plugin_build_mulaw(struct snd_pcm_substream *plug,
	269	struct snd_pcm_plugin_format *src_format,
	270	struct snd_pcm_plugin_format *dst_format,
	271	struct snd_pcm_plugin **r_plugin)
1da177e4 LT	272	{
1da177e4 LT	273	int err;
6ac77bc1 TI	274	struct mulaw_priv *data;
	275	struct snd_pcm_plugin *plugin;
	276	struct snd_pcm_plugin_format *format;
1da177e4 LT	277	mulaw_f func;
	278
	279	snd_assert(r_plugin != NULL, return -ENXIO);
	280	*r_plugin = NULL;
	281
	282	snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
	283	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
	284
	285	if (dst_format->format == SNDRV_PCM_FORMAT_MU_LAW) {
	286	format = src_format;
	287	func = mulaw_encode;
	288	}
	289	else if (src_format->format == SNDRV_PCM_FORMAT_MU_LAW) {
	290	format = dst_format;
	291	func = mulaw_decode;
	292	}
	293	else {
	294	snd_BUG();
	295	return -EINVAL;
	296	}
	297	snd_assert(snd_pcm_format_linear(format->format) != 0, return -ENXIO);
	298
	299	err = snd_pcm_plugin_build(plug, "Mu-Law<->linear conversion",
	300	src_format, dst_format,
6ac77bc1	301	sizeof(struct mulaw_priv), &plugin);
1da177e4 LT	302	if (err < 0)
1da177e4 LT	303	return err;
6ac77bc1	304	data = (struct mulaw_priv *)plugin->extra_data;
1da177e4 LT	305	data->func = func;
	306	data->conv = getput_index(format->format);
	307	snd_assert(data->conv >= 0 && data->conv < 422, return -EINVAL);
	308	plugin->transfer = mulaw_transfer;
	309	*r_plugin = plugin;
	310	return 0;
	311	}
21a3479a JK	312
21a3479a JK	313	#endif